Competing possibilities have been floated in recent days, with the preponderant view being that Mr. Hu, unlike his two predecessors, Jiang Zemin and Deng Xiaoping, will completely retire rather than stay on as the top overseer of military affairs. That would give Mr. Xi greater influence over the military and a firmer grip on power from the start.

But some insiders still suggest that Mr. Hu, who appears to have lost out to Mr. Jiang, 86, in shaping the new lineup for the top decision-making body, the Politburo Standing Committee, will nonetheless still hold on to the military post for two more years.

Whatever the outcome, the position, known as chairman of the Central Military Commission, is likely to be the last piece of leverage for Mr. Hu as top party officials tussle down to the wire over promotions of protégés and protection of long-held interests. The bargaining over whether Mr. Hu stays or goes is almost certainly fierce, party insiders said Monday.

Hu could complicate Xi’s efforts to consolidate power and create new room for political jockeying after China’s leadership transition was roiled by the downfall of former Politburo member Bo Xilai. A confused chain of command may muddle China’s handling of territorial disputes with Japan, at a time when the U.S. is concerned that Chinese leaders are using nationalism to paper over domestic tensions.

“When the party leadership is united, it’s obvious the party controls the gun,” Huang Jing, a political science professor at the National University of Singapore who expects Hu will stay on as military chief, said in a phone interview. “But when the party is divided or weak, whoever has the gun has the last say.”